A classic in most traditions, including the Italian one. This is my chocolate sponge cake with a cream layer in the middle, covered by a chocolate ganache. It is easy to make, however it does take a little time. The result is delicious and I make it as a birthday cake or at Easter.

Ingredients for the sponge (Pan di Spagna)
5 eggs (at room temperature)
1 vanilla pod
65 gr cornflower
65 gr cream flour
20 gr raw cocoa powder
150 gr Demerara sugar
1 pinch of salt
1 shot of rum or cognac + 1 tablespoon of sugar
Ingredients for the filling: custard (crema pasticcera)
4 eggs
1 vanilla pod
400 ml whole milk (or soy milk)
100 ml fresh single cream (or soy cream)
45 gr cornflour
140 gr Demerara sugar
Ingredients for the ganache
400 gr dark chocolate
200 gr heavy cream (or soy cream)
Method for the sponge
First of all it's great if you can do the sponge a day earlier than you need it. Do not cut it , just wait until it's properly cooled down and then cover with cling film. Do not put it in the fridge.
Put the eggs and the seeds from inside the vanilla pod into a biggish bowl, and whisk it up until they start to change colour and increase in volume
Add the sugar a bit at a time, continuing to whip it. It will be ready when a tablespoon of it drips down into a continuous line, which will lay "on top" of the cream, without immediately dissolving with the rest (like writing)
Sift all the dry ingredients and add them slowly through the sieve to the cream mixing from the bottom to the top to avoid disturbing the whipped state of the cream.
Have your cake tin ready, lined with baking paper and coated in melted butter. Pour the mixture in the tin and level with a small knife
Bake on the bottom rack of a pre-heated oven at 160 C for 50 minutes (150 C for a fan oven)
Test it with a stick in the center before taking it out of the oven, if the stick comes out clean the sponge is ready
Wait ten minutes before taking the cake out of the tin and place it onto a wire rack to cool down
Method for the chocolate custard
Take all seeds out of the vanilla pod. Reserve the seeds and put the empty pod in a pot with the milk and the cream. Heat up but don't let it reach the boiling point
Using a heavy pot, but not on the hob, whisk the eggs with the vanilla seeds and the sugar until they change colour and look quite creamy.
Gradually add the cornflower to the eggs using a sieve
Take the vanilla pod out of the milk and start adding the milk to the whipped eggs one ladlespoon at a time (take care to mix well, especially the first spoon or two) until you finish the milk
Place the pot on the hob and stir slowly on medium heat until the cream will be quite thick (remember you want to be able to spread it nicely)
Have a very big pot ready with cold water and icecubes, and place a bowl in it. Pour this custard into the bowl and stir it constantly until it is cool enough to eat. In this way the consistency of the custard will be maintained and stirring will prevent the skin to form (an alternative would be to cover the custard with cling film, making sure it touches the custard, and leave it to reach room temperature)
Assemble the cake
Take your sponge cake and cut it in half using a breadknife. Put 100 ml of water and the teablespoon of sugar into a small pot and let it dissolve completely. Take it off the heat and mix until it reaches room temperature. Add the glass of rum or congac
Wet lightly both halves of the sponge (the internal parts) with this syrup
Spread the custard on top of the bottom layer and wait a few minutes for it to settle. Cover it with the top layer
Method for the ganache
Break the chocolate in small enough pieces, put int into a bowl and microwave it for 1 minute
Pour the cream into another bowl and microwave for 1 minute (watch it, it must not boil)
Pour the heated cream into the chocolate bowl and wait 2 minutes, then start stirring slowly from the center rotating in one direction only until all the chocolate dissolves
Whisk it until you are sure that it's perfectly mixed. It will have of course a dark rich brown colour
Drizzle the ganache over the cake and spread it with a knife, trying to drip it and spread it over to cover the borders
Leave the cake to settle for two hours at room temperature to allow the ganache to harden before serving